From the Guidelines
Beta blockers are a class of medications that play a crucial role in managing various cardiovascular conditions, including heart failure, high blood pressure, and angina, by blocking the effects of adrenaline on beta-adrenergic receptors in the heart and blood vessels, as recommended by the 2013 ACCF/AHA guideline for the management of heart failure 1.
Key Characteristics of Beta Blockers
- They are primarily used to treat conditions such as high blood pressure, heart failure, abnormal heart rhythms, angina, and to prevent future heart attacks in people who have already had one.
- Common beta blockers include metoprolol (Lopressor, Toprol-XL), atenolol (Tenormin), propranolol (Inderal), carvedilol (Coreg), and bisoprolol (Zebeta).
- Beta blockers work by slowing heart rate, reducing the force of heart contractions, and decreasing blood pressure, which can lessen the symptoms of heart failure, improve the patient’s clinical status, and enhance the patient’s overall sense of well-being 1.
Dosage and Side Effects
- Typical dosing varies by medication and condition; for example, metoprolol may be prescribed at 25-100mg twice daily for hypertension, while propranolol might start at 40mg twice daily.
- Side effects can include fatigue, cold hands and feet, dizziness, and sometimes sleep disturbances.
- Beta blockers should not be stopped abruptly as this can trigger a rebound effect with increased heart rate and blood pressure.
Mechanism of Action
- Beta blockers work by competing with adrenaline for receptor sites, preventing the stress hormone from causing increased heart rate and blood pressure, which makes them effective for both cardiovascular conditions and sometimes anxiety-related symptoms.
- The use of beta blockers, such as bisoprolol, carvedilol, and sustained-release metoprolol succinate, is recommended for all patients with current or prior symptoms of heart failure with reduced ejection fraction (HFrEF), unless contraindicated, to reduce morbidity and mortality 1.
From the FDA Drug Label
Beta-adrenergic blocking agents do not abolish the inotropic action of digitalis on heart muscle Although beta-blockers should be avoided in overt congestive heart failure, some have been shown to be highly beneficial when used with close follow-up in patients with a history of failure who are well compensated and are receiving diuretics as needed. Beta-adrenergic blockade may prevent the appearance of certain premonitory signs and symptoms (pulse rate and pressure changes) of acute hypoglycemia, especially in labile insulin-dependent diabetics. Beta-adrenergic blockade may mask certain clinical signs of hyperthyroidism.
Beta blockers are a class of drugs that block the effects of the hormone epinephrine, also known as adrenaline, and cause the heart to beat more slowly and with less force. They are used to treat a variety of conditions, including:
- Hypertension (high blood pressure)
- Angina (chest pain)
- Heart failure
- Tachycardia (rapid heart rate)
- Thyrotoxicosis (a condition caused by an overactive thyroid gland) They work by blocking the beta receptors in the heart, which reduces the heart's workload and lowers its demand for oxygen. This can help to:
- Lower blood pressure
- Reduce the frequency and severity of angina attacks
- Slow the heart rate
- Improve the heart's pumping efficiency However, beta blockers can also have negative effects, such as:
- Worsening heart failure in some patients
- Masking symptoms of hypoglycemia (low blood sugar)
- Exacerbating bronchospasm (narrowing of the airways) in patients with asthma or chronic obstructive pulmonary disease (COPD) 2, 2, 2.
From the Research
Definition of Beta Blockers
- Beta blockers are a class of drugs that act by antagonizing the actions of the endogenous adrenergic agonists epinephrine and norepinephrine at the beta-adrenergic receptors 3
- They are used to treat various cardiovascular disorders, including hypertension, angina pectoris, and heart failure 4, 5, 6
Mechanism of Action
- Beta blockers work by blocking the effects of epinephrine and norepinephrine on the heart and blood vessels, which helps to reduce heart rate, blood pressure, and myocardial oxygen demand 3
- They can be selective or non-selective, with selective beta blockers targeting specific beta-adrenergic receptors (e.g. beta-1 or beta-2) 3
Types of Beta Blockers
- Examples of beta blockers include metoprolol, atenolol, propranolol, bisoprolol, and carvedilol 4, 3, 5, 6
- Some beta blockers, such as pindolol, have intrinsic sympathomimetic activity, which means they can cause some sympathetic stimulation under certain conditions 3